<template>
    <div class="sidebar">
        <el-menu class="sidebar-el-menu" :default-active="onRoutes" :collapse="collapse" background-color="#324157"
                text-color="#bfcbd9" active-text-color="#20a0ff" unique-opened router>
            <template v-for="item in items">
                <!-- 一级目录 -->
                <template v-if="item.subs">
                    <el-submenu :index="item.index" :key="item.index">
                        <template slot="title">
                            <svg-icon :icon-class="item.icon" /><span slot="title">{{item.title}}</span>
                        </template>
                        <template v-for="subItem in item.subs">
                            <!-- 二级目录 -->
                            <el-submenu v-if="subItem.subs" :index="subItem.index" :key="subItem.index">
                                <template slot="title">{{subItem.title}}</template>
                                <!-- 三级目录 -->
                                <el-menu-item v-for="(threeItem, i) in subItem.subs" :key="i" :index="threeItem.index">
                                    {{threeItem.title}}
                                </el-menu-item>
                            </el-submenu>
                            <el-menu-item v-else :index="subItem.index" :key="subItem.index">{{subItem.title}}</el-menu-item>
                        </template>
                    </el-submenu>
                </template>
                <template v-else>
                    <el-menu-item :index="item.index" :key="item.index">
                        <svg-icon :icon-class="item.icon"/><span slot="title">{{item.title}}</span>
                    </el-menu-item>
                </template>
            </template>
        </el-menu>
    </div>
</template>

<script>
import bus from '../common/bus'
export default {
    data() {
        return {
            collapse: false,
            items: [
                {
                    icon: 'home',
                    index: 'dashboard',
                    title: '系统首页'
                },
                {
                    icon: 'analysis-0',
                    index: 'table',
                    title: '基础表格'
                },
                {
                    icon: 'tabs',
                    index: 'tabs',
                    title: '编辑',
                    subs: [
                        {
                            index: 'markdown',
                            title: 'Markdown文本编辑'
                        }
                    ]
                },
                {
                    icon: 'analysis-1',
                    index: '3',
                    title: '表单相关',
                    subs: []
                }
            ]
        }
    },
    computed: {
        onRoutes() {
            return this.$route.path.replace('/', '');
        }
    },
    created() {
        // 通过 Event Bus 进行组件间通信，来折叠侧边栏
        bus.$on('collapse', msg => {
            this.collapse = msg;
        })
    }
}
</script>

<style scoped>
    .sidebar{
        display: block;
        position: absolute;
        left: 0;
        top: 70px;
        bottom:0;
        overflow-y: scroll;
    }
    .sidebar::-webkit-scrollbar{
        width: 0;
    }
    .sidebar-el-menu:not(.el-menu--collapse){
        width: 250px;
    }
    .sidebar > ul {
        height:100%;
    }
</style>